The current (August 4) trusty image is really a Debian Whezzy image.
This is the thread's initial revision.
I just tried https://rcn-ee.net/deb/rootfs/trusty/ubuntu-14.04-console-armhf-2014-07-06.tar.xz and found that it was a debian wheezy image instead of the advertized ubuntu image.
The previous image from that download location is working for me though. My apt-get upgrade has just finished successfully.